Effect of Nifedipine on Blood Pressure and on Intracellular Calcium in Arterial Hypertension

In 13 patients with essential and renal hypertension, the influence of nifedipine on the intracellular free Ca concentration was tested. Measurements of free Ca were performed with a Ca-selective electrode. The patients were additionally treated with a conventional antihypertensive combination therapy, by which the blood pressure could not be lowered satisfactorily. Under treatment with 30–60 mg of nifedipine daily, blood pressure was lowered from 192 ± 23/95 ± 15 mm Hg to 147 ± 20/83 ± 16 mm Hg. The intracellular Caactivity fell from 7,115 ± 14,139 to 1,886 ± 3,748 μmol/L (p < 0.05). The decrease in intracellular Ca correlated very well with the initial value of Ca activity (r = 0.966)furthermore, a relationship was found with the serum creatinine level (r = 0.48). On the other hand, there was no correlation with the decrease in blood pressure. In the lower dose range, nifedipine did not elicit a clear reduction in intracellular Ca. The results show that intracellular Ca activity can be influenced by Caantagonists, but that there is no direct relationship between intracellular free calcium and blood pressure.